You can get NetGuard on Android and see how often and what is called (facebook.com, graph.facebook.com, other vendors, platforms, IPs, etc). You can choose to block what is not needed. Kind of uBlockOrigin for Android. Sometimes stuff breaks.
You can go to your profile, and check which third parties, or advertisers uploaded contact data of you, download backup data to see in json files which apps what sent about you ("App activated", "Made some purchase").